Author Contributions:Study concept and design: Iida and Yanaga. Acquisition of data: Iida and Akita. Analysis and interpretation of data: Iida, Akita, Sasaki, and Hanyu. Drafting of the manuscript: Iida. Critical revision of the manuscript for important intellectual content: Iida, Akita, Sasaki, Hanyu, and Yanaga. Administrative, technical, and material support: Iida and Akita. Study supervision: Yanaga.